After playing the 1985 season for the Kentucky Wildcats, Leyritz went undrafted by Major League Baseball, but was signed as a free agent by the New York Yankees.[2] Leyritz made his MLB debut for the Yankees on June 8, 1990. His playing days were highlighted by a pair of walk off postseason home runs he hit with the Yankees in 1995 & 1996. He hit a walk off home run in the 15th inning of game 2 of the newly created American League Division Series against the Seattle Mariners, giving the Yankees a 2-0 series lead. However the Yankees lost the next three games in Seattle and were eliminated. The following year he hit a home run off Atlanta Braves closer Mark Wohlers in Game 4 of the 1996 World Series. That home run was significant, as the Yankees were down 2-1 in the series and had trailed 6-0 early in Game 4. facing a certain 3-1 deficit, the Yankees rallied and Leyritz's home run tied the score at 6. They eventually won game 4, tying the series at two games apiece and won the next two games to win the World Series . The home run has since become a part of Yankees lore.

On June 20, 1998, the Red Sox traded Leyritz with Ethan Faggett to the San Diego Padres for Carlos Reyes, Mandy Romero and Darío Veras. With the Padres, Leyritz appeared in the 1998 World Series against the Yankees. During player introductions in Game 1 at Yankee Stadium where the opposing team is usually booed, Leyritz received a standing ovation from the fans who remembered his heroics from two years earlier. He indirectly aided in another Yankees World Series win by going hitless in ten at bats in a four-game Yankees sweep.

On July 31, 1999, the Padres traded Leyritz to the Yankees for Geraldo Padua. He hit another World Series home run, this time, a solo home run in game 4, that provided the Yankees with an insurance run to help complete a sweep of the Atlanta Braves. On June 20, 2000, the Yankees traded Leyritz to the Los Angeles Dodgers for José Vizcaíno and cash.

Leyritz served as a pinch-hitter more extensively toward the end of his career. He batted and threw right-handed exclusively in the majors, but was known to switch-hit in the minor leagues. Leyritz is also known for hitting the last home run of the 1990s, in Game 4 of the 1999 World Series.

Leyritz was known for using an unusual stance which involved keeping his front leg (left leg) straight and stiff while his back leg (right leg) behind him considerably bent at the knee. He did this while circling his bat around behind his head, waiting for the pitch. After each pitch that Leyritz did not put into play or strike out on, he would grab the bat by its center and twirl it at his hip like a baton. He has said that former Yankee, Mickey Rivers, taught him how to twirl the bat at his hip.

Leyritz was also Andy Pettitte's personal catcher in 1995-96 and again in 1999-2000.

Leyritz is best known for hitting numerous postseason home runs that either won, tied, or changed the momentum of several series.

In Game 2 of the 1995 American League Division Series against the Seattle Mariners at Yankee Stadium, Leyritz hit an opposite field two-run home run to right-center into the rain in the 15th inning to win that game 7–5 for the Yankees and provided them with an ample 2–0 series lead in the best-of-five series. The home run came off Mariners pitcher Tim Belcher, who was famously involved in a profanity-laced and threatening incident with a cameraman covering him walking through the Yankee Stadium tunnel after giving up the home run. The Yankees would eventually squander the series lead by losing the following three games in Seattle's Kingdome, the final two of which were decided in highly dramatic fashion. (The Mariners won Game 5 by a score of 6–5 with two runs in the bottom of the 11th inning.)

The best known of Leyritz's playoff heroics occurred in Game 4 of the 1996 World Series against the Atlanta Braves at Atlanta-Fulton County Stadium. The Yankees had lost the first two games of the series at home, and narrowly won Game 3 in Atlanta. Game 4 appeared to be going to the Braves, who led 6–0 after 5 innings. The Yankees rallied for 3 runs in the 6th, setting the stage for Leyritz in the 8th inning. Leyritz stepped up with one out and two men on base and hit a three-run home run to left field to tie the game and cap the improbable Yankee comeback. "In the air to left field...back, at the track, at the wall, we are tied!" proclaimed Joe Buck, who was announcing the game on national television. The home run was hit against Atlanta closer Mark Wohlers and the Yankees eventually won the game 8–6 in 10 innings. Leyritz's Game 4 home run remains the most recognizable moment of that series and of his career. He then caught Andy Pettite and John Wetteland for a 1-0 shutout of the Braves in Game 5, with Wetteland eventually being named World Series MVP.

In 1998, Leyritz was on the San Diego Padres. Leyritz hit a number of unlikely playoff home runs and clutch hits that season, the most dramatic of which was an opposite field home run against Billy Wagner to off the right field foul pole in the top of the 9th inning in the Astrodome that tied Game 2 of the National League Division Series against the Houston Astros. However, the Astros would later win the game in the bottom of the ninth. In game 3, Leyritz hit the eventually game-winning home run off Randy Johnson in the bottom of the 7th inning that broke a 1–1 tie. Overall, Leyritz batted .400 with three home runs and five RBIs in that Division Series. Ironically, Leyritz's Padres would go up against his former team, the Yankees in the World Series. The Padres were swept in four games and Leyritz did not record a home run or RBI in any game.[3]

In 1999, Leyritz had rejoined the Yankees and hit a solo home run in the bottom of the 8th inning of Game 4 of the World Series. The home run made the score 4–1. NBC commentator Bob Costas remarked incredulously about Leyritz after the home run, "You could send this guy to a resort in the spring and summer, as long as he comes back for October." Including MLB postseason play, this was the last homerun hit in the 20th century[4]

On June 8, 2006, while doing an interview on the Opie and Anthony show on XM Satellite Radio, Leyritz admitted to using amphetamines after his shoulder surgery in 2001. The statement came in the wake of an admission by pitcher Jason Grimsley that he used performance enhancing drugs throughout his career.[8]

On December 28, 2007, Leyritz was arrested in Broward County, Florida on suspicion of drunk driving and vehicular homicide in which Leyritz's car struck Freida Veitch's car. Veitch, who was returning home from her bartending job, was not wearing a seat belt. She ejected from the car and died at the scene. Leyritz was released on US$11,000 bond and charged with two counts of drunk driving.[9]

Police collected two blood samples from Leyritz, the first 2½ hours after the crash and the second about an hour later. The first sample showed a blood-alcohol level of .14, and the second, .13, police said. Florida's legal limit for motorists is .08. Prosecutors say Veitch had a blood-alcohol level of .18.

Several days after the accident, it was revealed that Leyritz may face further charges because he had his license suspended in New York prior to the accident. On June 20, 2007, Leyritz was ticketed outside Albany, New York for using a cell phone while driving. On November 23, his license was suspended after he failed to appear in court. The state of Florida is processing the suspension notice from New York and could file additional charges once his Florida license is suspended. According to an official from the Florida Department of Highway Safety and Motor Vehicles: "The department has the statutory ability to suspend his license based on the fact he had knowledge of a suspension in another state and still came to Florida for a driver's license. It is unlawful." Leyritz's lawyer is quoted as saying that Leyritz's license "was not suspended in the state of Florida on the day of the accident, nor is it suspended today."[10]

On February 13, 2009, Leyritz was ordered back to jail as his bail was revoked following his apparent consumption of alcoholic beverages in violation with his bail conditions.[11] A judge allowed him to return home on bail on February 23 after agreeing with Leyritz's attorney that his pretrial release conditions were unclear and that Leyritz had misunderstood rather than intentionally violated the terms.[12]

On May 13, 2009, Leyritz was hospitalized in Florida. Reports on ESPN claimed Leyritz had threatened suicide, but Leyritz issued a statement later saying he was not suicidal but stressed out. Leyritz ran into trouble on May 14 when he attempted to start his car but the alcohol monitoring device on the car malfunctioned, leading to a false positive and triggering an automatic urine test for Leyritz. The test showed he had not consumed any alcohol and a judge cleared him.[13]

On July 2, 2009, Leyritz was arrested for battery against his former wife,[14] however the charges were later dropped[citation needed]. Leyritz chose not to press charges on his former wife for filing false charges.

In November 2010, Leyritz's trial for the December 2007 DUI crash was held. He was acquitted on the DUI Manslaughter charge by a jury in less than 45 minutes, but was convicted, after 2 days of dilberations, by the jury on a misdemeanor charge of driving under the influence, which carries a maximum sentence of six months in jail. He was subsequently sentenced to one year's probation and a $500 fine.[15] In May 2010, Leyritz's insurance company settled a civil lawsuit for the accident, paying $350,000 to the other driver's family.[16]

As of March, 2015, Leyritz lives in Orange County, California, with his two boys and his daughter, new fiance Michelle, and her two daughters. They plan on marrying in July of 2015. He is a member and usher at Saddleback Church in Lake Forest, California.

Leyritz is involved in with many charities. He is on the board of The Greatest Save/Kindervision Foundation which is designed to 'shut out' child predators.[17] He also works with many chapters of ALS, a disease he lost his brother-in-law, Joe Toerner, to in 2010.[18] During his playing days, Leyritz and his wife brought foster children to see games at Yankee Stadium and contributed to Covenant House and Police Benevolent Association.[1]

In October 2007, Jim worked with Harold Reynolds and Chris Myers covering the pre- and post-game reports on the field for the 2007 Playoffs and World Series for Fox.com.[citation needed]

January 6, 2014, Jim was hired to host a radio show for Angels Radio 830AM with Jason Brennan called "Inside The Game" with Leyritz and Brennan. The show was later postponed due to a conflict with ESPN radio.[citation needed]

Leyritz wrote a book titled Catching Heat: The Jim Leyritz Story, published in June 2011. The book was co-written by brothers Jeffrey Lyons and Douglas B. Lyons.[19] In a brief review, Publishers Weekly called the book "a surprisingly defensive attempt at a self-serving memoir."[20]